A battery charging system includes: an electric vehicle; a network termination unit connectable to the electric vehicle through a power line cable for supplying electric power to the electric vehicle; and a first server that transmits a control signal indicative of permission or forbiddance of power supply from the network termination unit to the electric vehicle to the electric vehicle through the network termination unit. The electric vehicle transmits identification information for identifying the electric vehicle and the user thereof to the first server through the network termination unit. The network termination unit transmits position information concerning the position of the network termination unit to the first server. The first server determines permission or forbiddance of the power supply based on the identification information and the position information.